US5630810A - Method of ophthalmological surgery - Google Patents
Method of ophthalmological surgery Download PDFInfo
- Publication number
- US5630810A US5630810A US08/606,504 US60650496A US5630810A US 5630810 A US5630810 A US 5630810A US 60650496 A US60650496 A US 60650496A US 5630810 A US5630810 A US 5630810A
- Authority
- US
- United States
- Prior art keywords
- eye
- corneal tissue
- corneal
- treatment
- tissue
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 54
- 238000001356 surgical procedure Methods 0.000 title claims abstract description 11
- 210000004087 cornea Anatomy 0.000 claims abstract description 52
- 230000000694 effects Effects 0.000 claims abstract description 25
- 230000003287 optical effect Effects 0.000 claims abstract description 21
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 13
- 230000000007 visual effect Effects 0.000 claims abstract description 11
- 230000001965 increasing effect Effects 0.000 claims abstract description 8
- 230000008859 change Effects 0.000 claims abstract description 3
- 238000011282 treatment Methods 0.000 claims description 84
- 210000001519 tissue Anatomy 0.000 claims description 65
- 230000015572 biosynthetic process Effects 0.000 claims description 24
- 210000000981 epithelium Anatomy 0.000 claims description 23
- 206010068150 Acoustic shock Diseases 0.000 claims description 17
- 239000012530 fluid Substances 0.000 claims description 15
- 238000012937 correction Methods 0.000 claims description 6
- 230000006378 damage Effects 0.000 claims description 6
- 230000005855 radiation Effects 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 4
- ISQINHMJILFLAQ-UHFFFAOYSA-N argon hydrofluoride Chemical compound F.[Ar] ISQINHMJILFLAQ-UHFFFAOYSA-N 0.000 claims description 3
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000002203 pretreatment Methods 0.000 claims 4
- 238000011221 initial treatment Methods 0.000 claims 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 12
- 238000002679 ablation Methods 0.000 description 11
- 201000009310 astigmatism Diseases 0.000 description 9
- 210000001525 retina Anatomy 0.000 description 8
- 208000001491 myopia Diseases 0.000 description 7
- 230000004379 myopia Effects 0.000 description 7
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000010926 purge Methods 0.000 description 5
- 206010052128 Glare Diseases 0.000 description 4
- 206010020675 Hypermetropia Diseases 0.000 description 4
- 230000015556 catabolic process Effects 0.000 description 4
- 238000006731 degradation reaction Methods 0.000 description 4
- 230000004438 eyesight Effects 0.000 description 4
- 230000004305 hyperopia Effects 0.000 description 4
- 201000006318 hyperopia Diseases 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 208000029257 vision disease Diseases 0.000 description 4
- 230000004393 visual impairment Effects 0.000 description 4
- 241001227713 Chiron Species 0.000 description 3
- 206010047571 Visual impairment Diseases 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 3
- 239000006196 drop Substances 0.000 description 3
- 201000000766 irregular astigmatism Diseases 0.000 description 3
- 230000008685 targeting Effects 0.000 description 3
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000004424 eye movement Effects 0.000 description 2
- 230000004313 glare Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000000608 laser ablation Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 208000003164 Diplopia Diseases 0.000 description 1
- 206010034960 Photophobia Diseases 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000003444 anaesthetic effect Effects 0.000 description 1
- 239000003242 anti bacterial agent Substances 0.000 description 1
- 230000003110 anti-inflammatory effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 230000004397 blinking Effects 0.000 description 1
- 230000003532 cataractogenesis Effects 0.000 description 1
- 230000006727 cell loss Effects 0.000 description 1
- 210000003683 corneal stroma Anatomy 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 210000002889 endothelial cell Anatomy 0.000 description 1
- 210000003560 epithelium corneal Anatomy 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000003889 eye drop Substances 0.000 description 1
- 229940012356 eye drops Drugs 0.000 description 1
- 210000000744 eyelid Anatomy 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000035876 healing Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 208000015181 infectious disease Diseases 0.000 description 1
- 238000013532 laser treatment Methods 0.000 description 1
- 208000013469 light sensitivity Diseases 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 230000009525 mild injury Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000003387 muscular Effects 0.000 description 1
- 231100000219 mutagenic Toxicity 0.000 description 1
- 230000003505 mutagenic effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 210000001747 pupil Anatomy 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 208000014733 refractive error Diseases 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 231100000241 scar Toxicity 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000000451 tissue damage Effects 0.000 description 1
- 231100000827 tissue damage Toxicity 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F9/00802—Methods or devices for eye surgery using laser for photoablation
- A61F9/00804—Refractive treatments
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00861—Methods or devices for eye surgery using laser adapted for treatment at a particular location
- A61F2009/00872—Cornea
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00897—Scanning mechanisms or algorithms
Definitions
- This invention relates to the field of ophthalmological surgery and specifically to a method of photorefractive keratectomy for improving the optical and refractive characteristics of an eye.
- the invention relates to a method of preventing the formation of central islands during photorefractive keratectomy.
- the human eye functions much like a camera in that light passes through the frontal portion of the eye and is focussed to produce an image on the rear surface or retina.
- the cornea Like film at the back of a camera, in order for an image to be seen clearly by the eye it must be focused precisely on the retina.
- eyeglasses or contact lenses are often used to correct the problem.
- corneal astigmatism occurs when the cornea is a football or toric shape with the two major meridians having radii of different lengths.
- the eye In the case of corneal astigmatism, the eye focuses at two different positions either in front or behind the retina causing a distortion or tilting of images received. In the case of hyperopia, a third form of visual impairment, the focal point of the eye is located behind the retina resulting in images that are out of focus, unless there is adequate muscular accommodation.
- Keratomileusis involves the removal of a portion of the cornea and reshaping it while frozen before replacing the corrected removed portion back onto the cornea.
- epikeratophakia the epithelium is removed and a synthetic or donor lenticle is sutured in place.
- Keratophakia involves placing a donor cornea/button into a pocket created in the patient's corneal stroma.
- Radial keratotomy is a significantly different procedure that involves the cutting of a number of deep radial incisions that extend from the optical zone to the periphery of the cornea. As a result of these incisions the peripheral cornea bulges outwardly causing central corneal flattening and a reduction of its reflective power that may correct myopia.
- Transverse keratotomics, or T-cuts as they are sometimes known, when made perpendicular to the astigmatic axis can correct astigmatism.
- each of these 5 methods can be useful when treating visual impairment of the types discussed, each also suffers from inherent problems. For example, keratomileusis may produce glare problems and sometimes creates irregular astigmatism.
- all these methods of refractive surgery have significant inherent problems; being primarily problems of predictability, ease of performing the procedure and surgical complications.
- extremely fine tolerances must be observed when removing or incising tissue. Extremely small variations in tolerances can result in significant diopter changes in refraction.
- a further problem with corneal surgery is that it is important that the procedure not impair the transparency or degrade the optical quality of the cornea.
- excimer laser keratectomy has been developed. With the introduction of ultraviolet lasers it was found that tissue from the anterior surface of the cornea could be removed through photoablution. Photoablution is the process where ultraviolet photons are absorbed by tissue molecules placing the molecules in a state of excitation. The increased energy state of the molecules "loosens” the bonds between the atoms causing the bonds to break in tiny bursts which can be described as very tiny explosions. The tissue under these conditions is said to "ablate”. Since the ablation process involves the breaking of molecular bonds without significant heating, tissue damage is limited to the area of exposure.
- the laser found to be best suited for this application is an argon fluoride excimer laser operating at a wavelength of 193 nm.
- argon fluoride excimer laser operating at a wavelength of 193 nm.
- corneal tissue can be removed with a high degree of precision and with virtually no damage to adjacent or underlying unexposed surfaces.
- Excimer laser machines have been developed that supply pulsed ultraviolet radiation calibrated to ablate corneal tissue to a precise known depth.
- Such a laser beam can be configured in any cross-sectional shape and is accurately controlled as it strikes the cornea through the use of computerization. This no-touch method allows a surgeon to remove corneal tissue precisely without fear of damaging surrounding tissue. Laser keratectomy can then be carried out without the problems associated with the use of mechanical cutting means such as in radial keratotomy.
- Narrow scanning laser beams suffer from their own inherent limitations and problem, however they are outside the general scope of this invention which deals more specifically with broad or wide beam configurations.
- Broad beam excimer lasers allow a surgeon to produce wide areas of photoablation such that the anterior surface of the cornea can be directly reprofiled to alter its optical power. For example, in the case of myopia, a portion of the central part of the cornea can be photoablated causing the cornea to be flattened with a corresponding reduction in dioptic power. Similarly through altering the targeting on the cornea, more tissue can be removed from the periphery of the cornea causing a steepening of the cornea to treat hyperopia. This process of correcting refractive error is commonly referred to as photorefractive keratectomy or PRK.
- central islands normally dissipates over time and normally within a few months they have either regressed or their effects have become only minimal. In more severe cases where central islands persist, they are retreated with a second excimer laser ablation confined specifically to the island itself.
- optic degradation theory Another theory advanced by some to explain the formation of central islands is known as the optic degradation theory.
- the theory is based upon the premise that central islands are formed as a result of the degradation of the optical characteristics of excimer lasers over time. Research has shown that this theory appears unsupportable since the incidence of central islands does not seem to vary between new and old lasers. One would expect that under the theory new lasers would have a lower incidence of central island formation.
- nitrogen purging and the use of alcohol to remove the epithelium should have no significant effect on central island formation. This has been found not to be the case.
- the invention therefore provides a method for overcoming the problems associated with photorefractive keratectomy by providing a method of improving the refractive characteristics of the eye through photoablation while minimizing or eliminating central island formation.
- the invention in one of its aspects provides an improved method of ophthalmological surgery to change the optical characteristics of an eye, through subjection to ultraviolet irradiation to volumetrically remove corneal tissue by way of photoablative decomposition, the method comprising the further step of subjecting a central portion of the cornea to increased ultraviolet irradiation and photoablative decomposition, over and above the irradiation of other corneal tissue, to increase qualitative visual results while not significantly changing the refractive characteristic of the cornea.
- the present invention provides a method of photorefractive keratectomy for making myopic or astigmatic corrections to an eye and thereby improving the refractive characteristics of the eye, the method comprising the steps of: (i) determining the portion of the cornea to be treated thereby defining a treatment area; (ii) selectively treating the anterior surface of the cornea by subjecting the central portion of the corneal tissue and epithelium in the treatment area to ultraviolet irradiation through the use of an excimer laser having a wavelength of 193 nm, whereby a portion of the corneal tissue, together with the overlying epithelium, is volumetrically removed through photoablative decomposition; and, (iii) subjecting the entire corneal tissue and epithelium in the treatment area to ultraviolet irradiation through exposure to said excimer laser causing volumetric removal of the epithelium, and volumetric removal of a predetermined depth of the corneal tissue, by means of photoablative decomposition.
- the present invention provides a method for reducing the incidence of central island formation in the cornea of an eye through minimizing the effects of acoustic shock waves within the eye's cornea during photorefractive keratectomy, the method comprising the steps of: (i) determining the portion of the cornea to be treated thereby defining a treatment area; (ii) removing the epithelium from the treatment area; (iii) forming a central hollow or detent, having a diameter of approximately 1 to 4 millimeters, in the corneal tissue through treating the central portion of said corneal tissue with an excimer laser having a wavelength of 193 nm; and (iv) subjecting the entire treatment area to irradiation through exposure to said excimer laser causing removal of a predetermined depth of corneal tissue, whereby acoustic shock waves created during the irradiation of the entire treatment area drive stromal fluid into the central area of the cornea.
- FIG. 1 is a schematic drawing showing the components of an excimer laser system pursuant to the invention
- FIGS. 2, 3, and 4 are schematical drawings of the cornea of an eye showing the effects of various photorefractive keratectomical procedures.
- central islands are commonly formed through the use of excimer lasers having a flat beam profile (such as the VISX Twenty/Twenty Excimer Laser and the Chiron Technolas Keracor 116 Excimer Laser).
- excimer lasers having a flat beam profile such as the VISX Twenty/Twenty Excimer Laser and the Chiron Technolas Keracor 116 Excimer Laser.
- central islands have been found to be essentially non-existent with excimer lasers having a Gaussian beam profile (such as the Summit ExciMed UV 200).
- a flat beam excimer laser has an energy profile with a generally "top-hat” shaped configuration with a marked distinction between the area within and outside the beam.
- the energy profile across the beam itself is relatively constant and homogeneous in a Gaussian beam profile the energy level of the beam increases toward its centre forming what is sometimes called a "hot" centre.
- the Gaussian lasers such as the Summit ExciMed LrV 200 produce essentially no central islands and do not utilize vacuum aspiration or nitrogen purging.
- the Summit ExciMed also has a pulse repetition rate of approximately twice that of the VISX Twenty Twenty flat beam laser, meaning that under the vortex plume theory the incidence of central islands should be greater as there is less time for plume dissipation.
- the present invention therefore discounts the vortex plume theory. Instead a new basis to explain the formation of central islands has been developed. This new basis shall be referred to as the Acoustic Shock Wave model.
- the Acoustic Shock Wave model Of underlying importance to the Acoustic Shock Wave model is the understanding that the excimer laser beam creates circular shock waves in the anterior stroma driving fluid both centrally and peripherally within the cornea.
- the intra-operative stromal hydration patterns are determined by the acoustic shock wave pattern, which is in turn related to the energy beam profile of the laser. Where there is progressive fluid accumulation there will be interference with oblation. That is, the stromal fluid accumulation blocks the successive pulses from the laser as the laser removes the fluid rather than the stromal tissue.
- eye drops are given to the patient beforehand. These drops can include an anesthetic to freeze the eye, an antibiotic to help prevent infection, an anti-inflammatory to reduce swelling and pain, and a pupil constrictor to reduce light sensitivity.
- an anesthetic to freeze the eye
- an antibiotic to help prevent infection
- an anti-inflammatory to reduce swelling and pain
- a pupil constrictor to reduce light sensitivity.
- An alignment system is activated on the excimer laser to align the treated eye with the laser equipment.
- a target light is utilized and the patient is instructed to focus his attention on the target light in order to stabilize eye movement.
- an eyelid speculum is inserted into the patient's treated eye. At this point the laser is programmed for the patient's prescription.
- the laser utilized in the procedure is an argon-fluoride gas ultraviolet laser having a wavelength of 193 nm.
- Other types of excimer lasers have been found to be unacceptable due to the characteristics of their radiation which can have mutagenic or cataractogenic effects.
- 193 nm ultraviolet radiation has been found to result in smooth ablation of tissue with negligible damage to surrounding tissue.
- FIG. 1 shows a typical laser system pursuant to the present invention.
- the laser console 1 typically comprises a laser head 2, a bridge unit 3, and an operating microscope 4.
- Incorporated within the console is also a power supply 5 and a microprocessor control 6 which includes a monitor 7 and a pulse control 8.
- the console is positioned next to a patient bed 9 such that the patient can lie upon the bed 9 with his or her eye positioned for treatment.
- Fixation means 10 used to assist in stabilizing patient eye movement, is attached to the laser console 1 over the patient bed 9.
- Normally fixation means 10 will comprise a non-irradiating targeting beam of light.
- the laser head 2 contains a series of optical lens that focus and control the laser beam 11.
- Laser head 2 also contains means 12 to vary the beam diameter such that treatment of the central corneal tissue can be carried out independently of the irradiation of the entire treatment area.
- Normally means 12 would comprise a variable diaphragm which may be opened or closed to produce a beam of desired diameter. Where the diaphragm is closed to produce a small diameter beam, the blocked portion of the beam will be absorbed by the diaphragm.
- beam diameter may be controlled through internal laser optics.
- the radiation is short pulsed and in the range of approximately 10 to 20 nanoseconds to minimize heat diffusion beyond the irradiated area. Pulses of this duration typically ablate a layer of tissue having a thickness of only a few molecules at a time to further reduce damage to adjacent tissue.
- the preferred fluence for the laser to operate at is 120 to 130 mj/cm2 which helps to promote optic longevity while reducing acoustic shock effects. It should be appreciated that both the pattern and the amplitude of acoustic shock waves play an important role in central island formation and that a fluence in the above range has been found to be optimal. Increasing laser fluence above these values has been shown to produce an undesirable thermal energy effect, increased degradation and increased acoustic shock wave effect. As has been determined by the present invention, it is the formation of such acoustic shock waves that can lead to the formation of central islands.
- a circular optical zone marker is applied to the surgery area of the treated eye thereby defining a treatment area.
- the epithelium is then removed from the treatment area through the use of the laser, through wiping with a blunt optical instrument (such as a Paton spatula) or through the application of diluted alcohol drops.
- a blunt optical instrument such as a Paton spatula
- a surgeon handpiece may be used to further immobilize the eye during the procedure.
- the first step involving the laser itself is the selective treatment of the central portion of the anterior surface of the cornea through subjecting the cornea in the treatment area to irradiation to ablate a portion of the tissue.
- This important first step is critical in the prevention of central island formation. It has been determined that when using the VISX Twenty Twenty Excimer Laser, for treatments of up to 6 diopters ablation of 1 micron per diopter is optimal. Ablation of about 0.6 microns per diopter has been found to be adequate for treatments above 6 diopters since large diameter treatments usually require deep ablations accomplished through multistep variable-diameter laser ablation.
- central corneal treatments of approximately 3 microns per diopter for treatment up to 3 diopters, 2.5 microns per diopter for treatments from 4 to 6 diopters, 2 microns per diopter for treatments from 7 to 9 diopters and 1.5 microns per diopter for treatments above 10 diopters are optimal. It has also been determined that treating an area of the cornea having a diameter of from 1 to 4 millimeters (with the preferable treatment zone being from 2 to 3 millimeters) in this manner is sufficient to prevent the formation of central islands.
- the entire treatment area of the cornea is subjected to irradiation causing volumetric removal of a predetermined depth of the corneal tissue through photoablative decomposition. That is, treatment of the central corneal tissue is in addition to full treatment of the entire treatment area and has no refractive effect. Rather, the procedure increases fie patient's qualitative vision and the ultimate optical performance of the patient's eye.
- a central hollow or detent is created in the corneal tissue. It has been found that with a central treatment area having a relatively small diameter, the energy profile across the laser beam is sufficiently constant to prevent the formation of central islands through the effects of acoustic shock waves. That is, with small diameter central treatment zones stromal fluid is not driven in opposing directions to form central islands. However, acoustic shock waves produced during the irradiation of the full treatment area drive stromal fluid into the hollow or detent. The central treatment is thereby blended into the ablation with the full treatment leaving a generally smooth treated corneal surface. Patients are not overtreated during the process as the central treatment only removes tissue that should be removed and that would not have been removed if it were not for the central treatment step.
- FIGS. 2, 3, and 4 show schematically in a simplified manner the net effect of the present invention as compared to the prior art. These Figures are meant to be simplified cross-sectional views of corneal tissue 13 that has been treated by photorefractive keratectomy.
- FIG. 2 depicts a central island 14 that often develops under current practices with current equipment.
- FIG. 3 shows the corneal tissue after treatment of the central treatment area where irradiation of this such area occurs as a pretreatment step.
- a detent 15 is shown as having been created in the cornea.
- FIG. 4 shows the net result of ablation of the entire treatment area where the detent 15 has been blended into the ablation of surrounding tissue to form a relatively smooth surface 16.
- central treatment detent In cases where patients would not normally have developed central islands, the relatively shallow central treatment detent has been found not to deleteriously effect the vision of the patient. It has been determined that the eye tolerates a facet or detent much better than a bump or central island. However, excessive central treatment (for the VISX Twenty Twenty excimer laser in excess of 2 microns per diopter) has been found to result in a refractive effect inducing hyperopia and may increase haze. Patients subjected to central treatment within the invention's parameters normally experience an improvement in qualitative vision due to an improvement in topography, even in those patients who would not have manifested a central island. In addition, with the current move toward larger optical treatment zones to reduce night glare and to improve wound contour to reduce haze and regression, central treatment pursuant to the present invention is even more important since the risk of central island formation increases with larger optical treatment zones.
- PTK phototherapeutic keratectomy
- the epithelium in the treatment area is removed by the excimer laser at the same time that the cornea is ablated.
- the steps of removing the epithelium over the central treatment area and the central treatment step are combined into a single procedure, as are the removal of the epithelium over the rest of the treatment area and the irradiation of the entire treatment area.
- the central treatment step may be carried into effect at different stages of the procedure.
- the central treatment will be carried out as the initial step of the procedure representing in effect a pretreatment step.
- the treatment of the central corneal tissue in the described manner may also be carried out simultaneously with the ablation of the entire treatment area or it may be carried out as a subsequent step following ablation of the treatment area.
- the two steps of the procedure should be carried out sufficiently close together in time such that significant epithelium healing has not occurred.
Landscapes
- Health & Medical Sciences (AREA)
- Ophthalmology & Optometry (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Optics & Photonics (AREA)
- Surgery (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Physics & Mathematics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Laser Surgery Devices (AREA)
Abstract
Description
Claims (10)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/606,504 US5630810A (en) | 1994-05-06 | 1996-02-23 | Method of ophthalmological surgery |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US23885794A | 1994-05-06 | 1994-05-06 | |
US08/606,504 US5630810A (en) | 1994-05-06 | 1996-02-23 | Method of ophthalmological surgery |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US23885794A Continuation | 1994-05-06 | 1994-05-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
US5630810A true US5630810A (en) | 1997-05-20 |
Family
ID=22899613
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/606,504 Expired - Fee Related US5630810A (en) | 1994-05-06 | 1996-02-23 | Method of ophthalmological surgery |
Country Status (1)
Country | Link |
---|---|
US (1) | US5630810A (en) |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6068625A (en) * | 1998-02-12 | 2000-05-30 | Visx Incorporated | Method and system for removing an epithelial layer from a cornea |
US6258082B1 (en) * | 1999-05-03 | 2001-07-10 | J. T. Lin | Refractive surgery and presbyopia correction using infrared and ultraviolet lasers |
US20030018348A1 (en) * | 2001-07-23 | 2003-01-23 | Ioannis Pallikaris | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20040220599A1 (en) * | 2001-07-23 | 2004-11-04 | Fos Holding S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20040260321A1 (en) * | 2002-12-19 | 2004-12-23 | Ming-Kok Tai | Apparatus and method for separating the epithelium layer from the cornea of an eye without corneal pre-applanation |
US20040260320A1 (en) * | 2002-12-10 | 2004-12-23 | Lisk James R. | Disposable separator for separating the epithelium layer from the cornea of an eye |
US20050107774A1 (en) * | 1999-05-03 | 2005-05-19 | Lin J. T. | Methods and apparatus for presbyopia correction using ultraviolet and infrared lasers |
US20050178394A1 (en) * | 2003-08-21 | 2005-08-18 | Intralens Vision, Inc. | Method for keratophakia surgery |
US7015039B1 (en) * | 2002-08-08 | 2006-03-21 | Massachusetts Eye & Ear Infirmary | Separating epithelium from stroma in LASEK surgery |
US20070055220A1 (en) * | 2003-11-14 | 2007-03-08 | Jui-Teng Lin | Methods and systems for treating presbyopia via laser ablation |
US20070173797A1 (en) * | 2006-01-26 | 2007-07-26 | Visx, Incorporated | Laser energy calibration based on optical measurement |
US20070173792A1 (en) * | 2003-03-06 | 2007-07-26 | Visx, Incorporated | Systems and methods for qualifying and calibrating a beam delivery system |
US20070265650A1 (en) * | 2001-07-23 | 2007-11-15 | Ioannis Pallikaris | Device for separating the epithelial layer from the surface of the cornea of an eye |
USRE40002E1 (en) | 1998-11-10 | 2008-01-15 | Surgilight, Inc. | Treatment of presbyopia and other eye disorders using a scanning laser system |
US7776086B2 (en) | 2004-04-30 | 2010-08-17 | Revision Optics, Inc. | Aspherical corneal implant |
US8057541B2 (en) | 2006-02-24 | 2011-11-15 | Revision Optics, Inc. | Method of using small diameter intracorneal inlays to treat visual impairment |
US8162953B2 (en) | 2007-03-28 | 2012-04-24 | Revision Optics, Inc. | Insertion system for corneal implants |
US8469948B2 (en) | 2010-08-23 | 2013-06-25 | Revision Optics, Inc. | Methods and devices for forming corneal channels |
US8668735B2 (en) | 2000-09-12 | 2014-03-11 | Revision Optics, Inc. | Corneal implant storage and delivery devices |
US8900296B2 (en) | 2007-04-20 | 2014-12-02 | Revision Optics, Inc. | Corneal inlay design and methods of correcting vision |
US9005280B2 (en) | 2000-09-12 | 2015-04-14 | Revision Optics, Inc. | System for packaging and handling an implant and method of use |
US9271828B2 (en) | 2007-03-28 | 2016-03-01 | Revision Optics, Inc. | Corneal implant retaining devices and methods of use |
US9345569B2 (en) | 2011-10-21 | 2016-05-24 | Revision Optics, Inc. | Corneal implant storage and delivery devices |
US9539143B2 (en) | 2008-04-04 | 2017-01-10 | Revision Optics, Inc. | Methods of correcting vision |
US9549848B2 (en) | 2007-03-28 | 2017-01-24 | Revision Optics, Inc. | Corneal implant inserters and methods of use |
USRE46493E1 (en) * | 2000-06-01 | 2017-08-01 | The General Hospital Corporation | Selective photocoagulation |
US10555805B2 (en) | 2006-02-24 | 2020-02-11 | Rvo 2.0, Inc. | Anterior corneal shapes and methods of providing the shapes |
US10583041B2 (en) | 2015-03-12 | 2020-03-10 | RVO 2.0 Inc. | Methods of correcting vision |
US10835371B2 (en) | 2004-04-30 | 2020-11-17 | Rvo 2.0, Inc. | Small diameter corneal inlay methods |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4665913A (en) * | 1983-11-17 | 1987-05-19 | Lri L.P. | Method for ophthalmological surgery |
US4669466A (en) * | 1985-01-16 | 1987-06-02 | Lri L.P. | Method and apparatus for analysis and correction of abnormal refractive errors of the eye |
US4718418A (en) * | 1983-11-17 | 1988-01-12 | Lri L.P. | Apparatus for ophthalmological surgery |
US4729372A (en) * | 1983-11-17 | 1988-03-08 | Lri L.P. | Apparatus for performing ophthalmic laser surgery |
US4732148A (en) * | 1983-11-17 | 1988-03-22 | Lri L.P. | Method for performing ophthalmic laser surgery |
US4770172A (en) * | 1983-11-17 | 1988-09-13 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
US4773414A (en) * | 1983-11-17 | 1988-09-27 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
CA1243732A (en) * | 1983-11-17 | 1988-10-25 | Francis A. L'esperance | Method and apparatus for ophthalmological surgery |
US4798204A (en) * | 1987-05-13 | 1989-01-17 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
US4856513A (en) * | 1987-03-09 | 1989-08-15 | Summit Technology, Inc. | Laser reprofiling systems and methods |
US4903695A (en) * | 1988-11-30 | 1990-02-27 | Lri L.P. | Method and apparatus for performing a keratomileusis or the like operation |
US4941093A (en) * | 1985-09-12 | 1990-07-10 | Summit Technology, Inc. | Surface erosion using lasers |
US4994058A (en) * | 1986-03-19 | 1991-02-19 | Summit Technology, Inc. | Surface shaping using lasers |
US5019074A (en) * | 1987-03-09 | 1991-05-28 | Summit Technology, Inc. | Laser reprofiling system employing an erodable mask |
US5108388A (en) * | 1983-12-15 | 1992-04-28 | Visx, Incorporated | Laser surgery method |
-
1996
- 1996-02-23 US US08/606,504 patent/US5630810A/en not_active Expired - Fee Related
Patent Citations (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1243732A (en) * | 1983-11-17 | 1988-10-25 | Francis A. L'esperance | Method and apparatus for ophthalmological surgery |
US4718418A (en) * | 1983-11-17 | 1988-01-12 | Lri L.P. | Apparatus for ophthalmological surgery |
US4729372A (en) * | 1983-11-17 | 1988-03-08 | Lri L.P. | Apparatus for performing ophthalmic laser surgery |
US4732148A (en) * | 1983-11-17 | 1988-03-22 | Lri L.P. | Method for performing ophthalmic laser surgery |
US4770172A (en) * | 1983-11-17 | 1988-09-13 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
US4773414A (en) * | 1983-11-17 | 1988-09-27 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
US4665913A (en) * | 1983-11-17 | 1987-05-19 | Lri L.P. | Method for ophthalmological surgery |
US5108388B1 (en) * | 1983-12-15 | 2000-09-19 | Visx Inc | Laser surgery method |
US5108388A (en) * | 1983-12-15 | 1992-04-28 | Visx, Incorporated | Laser surgery method |
US4721379A (en) * | 1985-01-16 | 1988-01-26 | Lri L.P. | Apparatus for analysis and correction of abnormal refractive errors of the eye |
US4669466A (en) * | 1985-01-16 | 1987-06-02 | Lri L.P. | Method and apparatus for analysis and correction of abnormal refractive errors of the eye |
US4941093A (en) * | 1985-09-12 | 1990-07-10 | Summit Technology, Inc. | Surface erosion using lasers |
US4994058A (en) * | 1986-03-19 | 1991-02-19 | Summit Technology, Inc. | Surface shaping using lasers |
US5019074A (en) * | 1987-03-09 | 1991-05-28 | Summit Technology, Inc. | Laser reprofiling system employing an erodable mask |
US4856513A (en) * | 1987-03-09 | 1989-08-15 | Summit Technology, Inc. | Laser reprofiling systems and methods |
US4798204A (en) * | 1987-05-13 | 1989-01-17 | Lri L.P. | Method of laser-sculpture of the optically used portion of the cornea |
US4903695A (en) * | 1988-11-30 | 1990-02-27 | Lri L.P. | Method and apparatus for performing a keratomileusis or the like operation |
US4903695C1 (en) * | 1988-11-30 | 2001-09-11 | Lri L P | Method and apparatus for performing a keratomileusis or the like operation |
Non-Patent Citations (16)
Title |
---|
Central Photorefractive Keratectomy for Myopia, MacDonald et al., Jun. 1990. * |
Central Photorefractive Keratectomy for Myopia, MacDonald et al., Sep. 1991. * |
Changes in Corneal Topography after Excimer Laser Photorefractive Keratectomy for Myopia, Wilson et al., Date of Publication Unknown. * |
Corneal topography following excimer photorefractive keratectomy for myopia, Lin et al., 1993. * |
Corneal topography: In Search of the Excimer Islands, Gilbert, Fall 1993. * |
Elements of Ultraviolet Laser Ablation, Srinivasan, Date of Publication Unknown. * |
Excimer Laser (193 nm) Myopic Keratomileusis in Sighted and Blind Human Eyes, Seiler et al., Jun. 1990. * |
Excimer Laser Photorefractive Keratectomy, Gartry et al., Aug. 1992. * |
Excimer Laser Surgery of the Cornea, Trokel et al., Dec. 1983. * |
Laser Corneal Surgery, Steinert et al., 1988. * |
Long term Healing of the Central Cornea after Photorefractive Keratectomy Using an Excimer Laser, Marshall et al., Oct. 1988. * |
Long-term Healing of the Central Cornea after Photorefractive Keratectomy Using an Excimer Laser, Marshall et al., Oct. 1988. |
On the Safety of 193 Nanometer Excimer Laser Refractive Corneal Surgery, Van Meilaert et al., 1992. * |
On the Safety of 193-Nanometer Excimer Laser Refractive Corneal Surgery, Van Meilaert et al., 1992. |
Philosophy and Technique for Excimer Laser Phototherapeutic Keratectomy, Thompson et al., Mar. 1993. * |
Photoablative reprofiling of the cornea using an excimer laser: Photorefractive keratectomy, Marshall et al., 1986. * |
Cited By (44)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6068625A (en) * | 1998-02-12 | 2000-05-30 | Visx Incorporated | Method and system for removing an epithelial layer from a cornea |
USRE40002E1 (en) | 1998-11-10 | 2008-01-15 | Surgilight, Inc. | Treatment of presbyopia and other eye disorders using a scanning laser system |
US20070005046A1 (en) * | 1999-05-03 | 2007-01-04 | Lin J T | Methods and apparatus for presbyopia correction using ultraviolet and infrared lasers |
US6258082B1 (en) * | 1999-05-03 | 2001-07-10 | J. T. Lin | Refractive surgery and presbyopia correction using infrared and ultraviolet lasers |
USRE40184E1 (en) * | 1999-05-03 | 2008-03-25 | Surgilight, Inc. | Refractive surgery and presbyopia correction using infrared and ultraviolet lasers |
US20050107774A1 (en) * | 1999-05-03 | 2005-05-19 | Lin J. T. | Methods and apparatus for presbyopia correction using ultraviolet and infrared lasers |
US7275545B2 (en) | 1999-05-03 | 2007-10-02 | Surgilight, Inc. | Methods and apparatus for presbyopia correction using ultraviolet and infrared lasers |
USRE46493E1 (en) * | 2000-06-01 | 2017-08-01 | The General Hospital Corporation | Selective photocoagulation |
US9889000B2 (en) | 2000-09-12 | 2018-02-13 | Revision Optics, Inc. | Corneal implant applicators |
US9005280B2 (en) | 2000-09-12 | 2015-04-14 | Revision Optics, Inc. | System for packaging and handling an implant and method of use |
US8668735B2 (en) | 2000-09-12 | 2014-03-11 | Revision Optics, Inc. | Corneal implant storage and delivery devices |
US7708750B2 (en) | 2001-07-23 | 2010-05-04 | Fos Holdings S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US7156859B2 (en) | 2001-07-23 | 2007-01-02 | Fos Holding S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US7004953B2 (en) | 2001-07-23 | 2006-02-28 | Fos Holding S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20040167555A1 (en) * | 2001-07-23 | 2004-08-26 | Fos Holding S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20030018348A1 (en) * | 2001-07-23 | 2003-01-23 | Ioannis Pallikaris | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20030018347A1 (en) * | 2001-07-23 | 2003-01-23 | Ioannis Pallikaris | Device for separating the epithelium layer from the surface of the cornea of an eye |
US20050288696A1 (en) * | 2001-07-23 | 2005-12-29 | Pallikaris Ioannis G | Device for separating the epithelial layer from the surface of the cornea of an eye |
US20070265650A1 (en) * | 2001-07-23 | 2007-11-15 | Ioannis Pallikaris | Device for separating the epithelial layer from the surface of the cornea of an eye |
US20040220599A1 (en) * | 2001-07-23 | 2004-11-04 | Fos Holding S.A. | Device for separating the epithelium layer from the surface of the cornea of an eye |
US7015039B1 (en) * | 2002-08-08 | 2006-03-21 | Massachusetts Eye & Ear Infirmary | Separating epithelium from stroma in LASEK surgery |
US20040260320A1 (en) * | 2002-12-10 | 2004-12-23 | Lisk James R. | Disposable separator for separating the epithelium layer from the cornea of an eye |
US20040260321A1 (en) * | 2002-12-19 | 2004-12-23 | Ming-Kok Tai | Apparatus and method for separating the epithelium layer from the cornea of an eye without corneal pre-applanation |
US20070173792A1 (en) * | 2003-03-06 | 2007-07-26 | Visx, Incorporated | Systems and methods for qualifying and calibrating a beam delivery system |
US8968279B2 (en) | 2003-03-06 | 2015-03-03 | Amo Manufacturing Usa, Llc | Systems and methods for qualifying and calibrating a beam delivery system |
US20050178394A1 (en) * | 2003-08-21 | 2005-08-18 | Intralens Vision, Inc. | Method for keratophakia surgery |
US20070055220A1 (en) * | 2003-11-14 | 2007-03-08 | Jui-Teng Lin | Methods and systems for treating presbyopia via laser ablation |
US10835371B2 (en) | 2004-04-30 | 2020-11-17 | Rvo 2.0, Inc. | Small diameter corneal inlay methods |
US7776086B2 (en) | 2004-04-30 | 2010-08-17 | Revision Optics, Inc. | Aspherical corneal implant |
US7811280B2 (en) * | 2006-01-26 | 2010-10-12 | Amo Manufacturing Usa, Llc. | System and method for laser ablation calibration |
US20070173797A1 (en) * | 2006-01-26 | 2007-07-26 | Visx, Incorporated | Laser energy calibration based on optical measurement |
US8057541B2 (en) | 2006-02-24 | 2011-11-15 | Revision Optics, Inc. | Method of using small diameter intracorneal inlays to treat visual impairment |
US10555805B2 (en) | 2006-02-24 | 2020-02-11 | Rvo 2.0, Inc. | Anterior corneal shapes and methods of providing the shapes |
US8540727B2 (en) | 2007-03-28 | 2013-09-24 | Revision Optics, Inc. | Insertion system for corneal implants |
US9549848B2 (en) | 2007-03-28 | 2017-01-24 | Revision Optics, Inc. | Corneal implant inserters and methods of use |
US9271828B2 (en) | 2007-03-28 | 2016-03-01 | Revision Optics, Inc. | Corneal implant retaining devices and methods of use |
US9877823B2 (en) | 2007-03-28 | 2018-01-30 | Revision Optics, Inc. | Corneal implant retaining devices and methods of use |
US8162953B2 (en) | 2007-03-28 | 2012-04-24 | Revision Optics, Inc. | Insertion system for corneal implants |
US8900296B2 (en) | 2007-04-20 | 2014-12-02 | Revision Optics, Inc. | Corneal inlay design and methods of correcting vision |
US9539143B2 (en) | 2008-04-04 | 2017-01-10 | Revision Optics, Inc. | Methods of correcting vision |
US8469948B2 (en) | 2010-08-23 | 2013-06-25 | Revision Optics, Inc. | Methods and devices for forming corneal channels |
US9345569B2 (en) | 2011-10-21 | 2016-05-24 | Revision Optics, Inc. | Corneal implant storage and delivery devices |
US9987124B2 (en) | 2011-10-21 | 2018-06-05 | Revision Optics, Inc. | Corneal implant storage and delivery devices |
US10583041B2 (en) | 2015-03-12 | 2020-03-10 | RVO 2.0 Inc. | Methods of correcting vision |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5630810A (en) | Method of ophthalmological surgery | |
US7275545B2 (en) | Methods and apparatus for presbyopia correction using ultraviolet and infrared lasers | |
US6824540B1 (en) | Apparatus and methods for the treatment of presbyopia using fiber-coupled-lasers | |
US6745775B2 (en) | Methods and apparatus for presbyopia treatment using a scanning laser system | |
US6263879B1 (en) | Treatment of presbyopia and other eye disorders using a scanning laser system | |
US6342053B1 (en) | Apparatus for cornea reshaping | |
AU2006238845B2 (en) | Methods for treating hyperopia and presbyopia via laser tunneling | |
US5411501A (en) | Laser reprofiling system for correction of astigmatisms | |
L'Esperance et al. | Human excimer laser keratectomy: short-term histopathology | |
US20060155265A1 (en) | Method of corneal surgery by laser incising a contoured corneal flap | |
US20050043722A1 (en) | Methods and apparatus for treatment of eye disorders using articulated-arm-coupled ultraviolet lasers | |
US20050279369A1 (en) | Method and apparatus for the treatment of presbyopia and glaucoma by ciliary body ablation | |
US20030139737A1 (en) | Method and apparatus for treatment of presbyopia by lens relaxation and anterior shift | |
US20060129141A1 (en) | Treatment of eye disorders using articulated-arm coupled ultraviolet lasers | |
JP2004525738A6 (en) | Method and apparatus for correcting presbyopia using ultraviolet and infrared lasers | |
USRE40002E1 (en) | Treatment of presbyopia and other eye disorders using a scanning laser system | |
JPH0355B2 (en) | ||
CA2505046A1 (en) | Methods and systems for treating presbyopia via laser ablation | |
EP0412789A1 (en) | Laser ablation of surfaces | |
Ren et al. | Laser refractive surgery: a review and current status | |
US20040078030A1 (en) | Methods and apparatus for presbyopia treatment using a dual-function laser system | |
CA2123042A1 (en) | Apparatus and method of opthalmological surgery | |
EP0654985B1 (en) | Laser reprofiling system for correction of astigmatisms | |
Lin | Mini-excimer laser corneal reshaping using a scanning device | |
Telfair et al. | Evaluation of corneal ablation by an optical parametric oscillator (OPO) at 2.94 um and an Er: YAG laser and comparison to ablation by a 193-nm excimer laser |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: TLC THE LASER CENTER PATENTS, INC., CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MACHAT, JEFFERY J.;VAMVAKAS, ELIAS;TLC THE LASER CENTER, INC.;REEL/FRAME:009516/0900 Effective date: 19980821 |
|
AS | Assignment |
Owner name: TLC THE LASER CENTER, INC., CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MACHAT, JEFFREY J.;REEL/FRAME:009525/0037 Effective date: 19980821 Owner name: VAMVAKAS, ELIAS, CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MACHAT, JEFFREY J.;REEL/FRAME:009525/0037 Effective date: 19980821 |
|
RF | Reissue application filed |
Effective date: 19990519 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: HELLER HEALTHCARE FINANCE, INC., MARYLAND Free format text: SECURITY INTEREST;ASSIGNORS:LASERSIGHT INCORPORATED;LASERSIGHT TECHNOLOGIES, INC.;LASERSIGHT CENTERS INCORPORATED;AND OTHERS;REEL/FRAME:012802/0276 Effective date: 20010312 |
|
AS | Assignment |
Owner name: GENERAL ELECTRIC CAPITAL CORPORATION, MARYLAND Free format text: ASSIGNMENT OF SECURITY AGREEMENT;ASSIGNOR:GE HFS HOLDINGS, INC., FORMERLY HELLER HEALTHCARE FINANCE, INC.;REEL/FRAME:014646/0908 Effective date: 20040506 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20050520 |